Question #804cf

1 Answer
Aug 26, 2017

Because the reaction produces hydrogen gas.


Magnesium metal will react with hydrochloric acid to produce aqueous magnesium chloride, #"MgCl"_2#, and hydrogen gas, #"H"_2#.

#"Mg"_ ((s)) + 2"HCl"_ ((aq)) -> "MgCl"_ (2(aq)) + "H"_ (2(g)) uarr#

The hydrogen gas produced by the reaction will bubble out of the solution--this is what the up arrow added next to #"H"_2# in the balanced chemical equation means--which is what you're seeing when this reaction takes place.

So it's not the magnesium metal itself that fizzles and bubbles, it's the hydrogen gas produced by the reaction.